Ship&#39;s-course indicator.



PATBNTED AUG. 23, 1904.

C. P. JONES. SHIPS COURSE INDICATOR.

APPLIUATION FILED APR. 18, 1903.

N0 MODEL.

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UNITED STATES Patented August 23, 1904.

PATENT @Erica SHlPS-COURSE INDICATOR.

SPECIFICATION forming part of Letters Patent No. 768,330, dated August23, 1904. Application tiled April 18, 1903. Serial No. 153,278. (Nomodel.)

To n/ZZ 'wiz/mit t 77mg/ 0072.067172:

Be it known that I, CHARLES PRYCE J oNEs, a citizen ot' the UnitedStates of America, residing' in Oxton, Birkenhead, in the county ofChester, England, have invented a certain new and useful ImprovedShips-Course Indicator, of which the following is a specification.

This invention relates to an improved instrument Jfor determining thecompass course of a ship from the true course as indicated on the chartor for determining the true course from the compass course; and theobject is to provide an instrument which when laid on the chart shallenable the navigator to determine in a purely automatic or mechanicalmanner the proper compass course to steer, the necessary correction forcompass error being made in the instrumentitseli', the use of which alsodispenses with the necessity for using parallelrulers, protractors, andthe like. The instrument can also be used for the reverse processA viz.,the determination oi' the true course from the compass course.

I have illustrated my invention in the accompanying drawings, in which-Figure l is an elevation oi' the instrument; Fig. 2, an elevation inmedial section; Fig. 3, a plan; Fig. 4, a detail view showing one of thesegments.

The instrument, as illustrated in the drawings, comprises a ring l witha beveled eX- ternal edge 2, on which, as well as on the face 3, thefour cardinal points of the compass are marked, the right angles inbetween being graduated in degrees. Across the open center of the ringare a pair of cross-wires 4, intersecting at right angles at the center.The body of the ring has an annular recess 5, in which four segments A,B, C, and D, also graduated in degrees, are adapted to tit, and.

in which they may be rotated about the center oi' the ring. One pair ofsegments, A and B, are marked True course to compass course, and one ofthe pair, A, is used and marked for an easterly correction and one, B,for a westerly correction. The other pair, C and D, are marked Compasscourse to true course, and the respective segments for this pair C and'Dvpiece 12 by the hinge 13, is used.

are marked and used for easterly and westerly corrections. The annularrecess has an annular groove 6 formed in each side, and the segments areeach provided with a pair of tongue-pieces 7, which fit in the groovesand keep the quadrants in position. The segments are inserted inposition by first inserting the outer tongue-piece in the outer grooveand bringing the inner tongue-piece over the notch S, which is afterwardcovered by the pivoted arm 9. In order to more clearly read thegraduations, a magnifying-lens 10, carried by an arm ll, hinged to thecircular To permit the rotation of the lens, the circular piece l2 iscarried in a central annular groove and is held in place by thecover-piece lei, secured to the ring l by the screwed knobs l5, whichconveniently serve as handles to manipulate the instrument. Thesesegments may be distinguished, in addition to their marking, by beingcolored in a distinctive manner.

The instrument is used as follows: Assuming the course is indicated onthe chart by a line G G, the instrument is placed so that thecross-lines intersect on this line and so that the respective cardinalpoints N. and S. or E. and IV. are coincident, respectively, withmeridians oi' longitude or parallels of latitude as marked on the chart.The anglethirty degrees in the case illustrated-the courseline makeswith the N. S. line may then be read ott the beveled and graduated edge.This angle would give the course to be steered if there were no compasserror-viz., S. 30O E.-but in order to take this latter error intoaccount one ot' the segments referred to is used. Assume that thecompass error was known to be lOO IV. then the segment marked Truecourse to compass course-error west would be inserted in the annulargroove with its zero-point opposite the line of the course, and thecorrect compass course to steer would then be read oil' the beveled edgejust opposite the graduation l()O on the segmentviz., S. 2()O E. It' theerror had been, say, 7@ E., then the other segment of this pair wouldhave been employed, its zero brought opposite the courseline, and thecorrect compass course read off opposite the graduation Tcl-viz., S. 370E. 'Io change compass course into true course,the other pair ofsegments, either E. or WV., as the case may be, would be employed.

The segments are graduated, as shown in the drawings that is to say, inthe pair marked 'Irue course to compass course the graduations arefigured in A for an easterly compass error from the zero point in a Ccounter-clockwise direction and 1n B for a westerly error from theZero-point in a clockwise direction. In the pair C and D, marked Compasscourse to true course, the marking is of course in the reverse directionfrom zero, respectively, to that described.

It will be seen that the operation is a purely mechanical one and thereis no difficulty in selecting the right segment, as they are plainlymarked.

By the use of the instrument the confusion in the mind as to whethereasterly or westerly compass errors have to be respectively added to orsubtracted from westerly or easterly courses is entirely obviated.

I have described the four segments as being quite separate and as being'guided by the grooves. They may, however, be guided in any suitablemanner say, by means of a central pivotand two of the segments may becombined in one, though I prefer, in order to make the operation apurely mechanical one, to use the four. as described.

Having now fully described my invention, what I claim, and desire tosecure by Letters Patent, is

l; In a course-indicator, in combination, a graduated circle on whichthe four cardinal points are marked, and having an open central portionin which the center of the circle is marked; and graduated segmentsoppositely figured as described and adapted to move concentrically roundthe circle with the graduations thereof in juxtaposition to thegraduations of the circle; substantially as described.

2. In a course-indicator, in combination, a graduated circle on whichthe four cardinal points are marked, and having' an open central portionacross which a pair of wires are fixed, intersecting at right angles atthe center, the said circle having a concentric recess formed in theface thereof; and graduated segments oppositely figured as described,adapted to fit the said recess and to move concentrically round thecircle with their graduations in juxtaposition to the graduations of thecircle; substantially as described.

3. In a course-indicator, in combination, a

circle with an open central part and havinga beveled edge and aconcentrically-recesscd face, the beveled edge and the portion of theface outside the recess being graduated and marked with the fourcardinal points; a pair of wires intersecting at right angles at thecenter; and graduated segments oppositely figured as described, andadapted to fit the recess and to move concentrically round the circlewith their graduations in juxtaposition to the graduations of thecircle; substantially as described.

4f. In a course-indicator, in combination with the graduated circle, twopairs of segments movable independently of each other, one pair beingdistinguished from the other, and one segment of each pair having itsgraduations figured from zero in clockwise direction, and the othersegment of each pair having its graduations figured from Zero in acounter-clockwise direction; substantially as described.

5. In a course-indicator, in combination with the graduated circle; twopairs of segments, one pair, distinguished from the other, being markedTrue to compass, one seg'- ment of this pair having its graduationsmarked from Zero counter-clockwise and being marked Error east, and theother seg'- ment having its graduations oppositely figured and beingmarked Error west the other pair being each marked Compass to true, onesegment having its graduations figured from Zero counter-clockwise andbel t ing marked Error west and the other having its graduationsoppositely igured and being marked Error east; substantially asdescribed.

6. In a course-indicator, in combination, a graduated circle having' anannular recess with grooved sides one of which is notched and providedwith a cover and segments having tongue-pieces adapted to fit thegrooves and to keep the seg-ments in position; substantially asdescribed.

7. In a course-indicator, in combination, the graduated circle, thesegments movable independently of each other and of the graduatedcircle, and the magnifying-lens mounted by means of a hinged stem on acircular piece rotatively attached to the graduated circle;substantially as described.

In testimony whereofl I have hereunto set my hand in the presence of twosubscribing witnesses.

` CHARLES PRYCE JONES. W'itnesses:

J. E. LLOYD BARNES, A JOSEPH E. HIRs'r.

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